Then video showing five security guards viciously kicking and elbowing two Australian tourists outside a nightclub on the island went viral on the internet.

Now, the island's serenity has been shattered further as an angry mob surrounded a police station and set alight nine cars in protests at the deaths of two locals.

Hundreds of army reinforcements arrived from neighbouring provinces as a mob threatened to set the Thalang police station in central Phuket alight, with police cowering inside on Saturday and early Sunday.

Photographs from inside the police building showed police sheltering in an upper floor. Some windows were smashed.

Up to 500 people outside the building dispersed early on Sunday after a senior military officer promised that their grievances would be heard at a mediation meeting.

The online news site Phuketwan reported that a youth aged 17 and a man aged 22 died on Saturday when the motorcycle they were riding crashed.

Police said the pair rode off after being stopped by police on suspicion of possessing illegal drugs.

Gatherings of Thais and public protests have been rare in Thailand since the army toppled a democratically-elected government last year, after months of anti-government street demonstrations.

The ruling junta has moved swiftly to crush dissent, including taking away hundreds of people to military camps for so-called "re-education".

The haze that has shrouded parts of southern Thailand from forest fires in Indonesia cleared at the weekend.

Meanwhile, the five security guards seen in video assaulting the Mildura men on an end-of-season football trip will escape punishment because the victims left Thailand without making statements to police.